Hydraulic propulsion system for boats



Oct. 25, 1949. E. c. c. MILLER HYDRAULIC PROPULSION SYSTEM FOR BOATSFiled Dec. 6, 1945 E. OH

0N oN.

Patented Oct. 25, 1949 UNITED STATES PATENT OFFICE HYDRAULIC PROPULSIONt SYSTEM FOR 'BOATS Ernest C. C. Miller, Laurelton, N. Y.

Application December .6, 1945, Serial No. 633,117.6

7 Claims. 1

This inventionis'ahydraulic propulsion system for boats, especially forsmaller, :power driven boats, suchas launches, motor boats, and thelike.

Withthe usual screwjpropelled boat, the engine is .generally iinthesternfof the boat and drives `a propeller shaft, `sloping'diagonallyand rearwardly through ithe bottom of the boat. Such engine must becarefully alignedrwith the propeller shaft, andthe propeller vshaftpasses through a bearing :which must be tight enough to keep out theWater., `and ymust be .adequately lubricated. The mounting 4of theengine and the propeller shaft as ziust described, requires Ia.considerable degree ofskill'an'dzadds considerably to the costofmanufacture ofthe fboat.

One :of 'the :most important. features of the present invention is vtoeliminate the yusual propeller shaft .passing :through the bottom of.the boat, thereby, of course, eliminating the expense of the shaft,.the expense rof installing it, and the -use of lubricated `bearingsvand packings for accommo'dating suohshaft.

The engine o'f :a motor boat also is rigidly mounted ;in `.the hull, -asit must be to keep'its alignment with :the ypropeller .shaft. With sucha .rigid mounting, vthe vibration of the engine, especially with highpowered engines, iis considerab1e,'an'dfis communicated to the hull ofthe boat.

Another :important :feature of .the invention .is to` mount `the engine.on .aresilientrshook absorbing .and :vibration absorbing Tbase, so.that the vibration 'from 4'the engine is not communicated to the hullof the boat, with the result that the operation of the boatis :quietandsrnootn'as compared with one-where the yengine isrgidly. mounted lintthe usual Way.

'Withthe usual motor boat, :the engine isfgenerallyin .the center of the:boat and sometimes isfveryrmuchA in the Way. :Another important featureof this invention is that the engine :need notbe mountedfin the centernf.the `boatin alignment withithepropellerishaft,1but;maybe .mountedinzanypconvenient .placeand may even extend transversely of the xhull,rather .than longitudinally, if such arrangement is desired.

"The foregoing and other .advantages 4are achieved by lthis invention,wherein thepropeller is :not mechanically Aconnected to 'fthe engine'but is :drivenby a hydraulic motor, lthe fluid 4pressure for actuating'the motor coming 'from a fpump driven'bythe engine. The pressure pumpis connected .to the hydraulic motor by metallic pipes or bynonm'etallichose, such pressurepipes or hose extending .from `the pump,'located in the peller.

.-2 boat, to the yhydraulic motor located-outboard-of the vboat, Athesepipes extending over the .gunwale at the stern or vthrough the stern-aboveor Lbelow the water line, or even vthrough the .bottom voftheboat.

Another valuable .feature of the .invention, re sulting from -the use ofthe hydraulic drive, is-.a graded .control --of the ,propeller .speed:and ready reversibility of the propeller, both .achieved by manuallyoperated valve means ycontrolling the amount of pressure uidsuppliedtothe .hydraulic motor. Gradual movement of the valve gradually variesthepressure andamountnf the .pressurefluid, to gradually .vary thespeedof the ,pro-

The uid .flow to the hydraulic .motor may-readily be reversed by .thevalve, thereby reversing .the lpropeller. The described `controls `of-the propeller may `be effected without changing the Fspeed vorldirection Vof rotation of the .engine orpump, and .without.theluse-ofgears or clutches, which are used to achieve .similar resultswith .a mechanical drive.

.Another .important Yfeature .of the invention is thatthe boatmay .hesteered by pivoting .the propeller soas ,to .be moved to portforstarboard about a verticalaxis, thereby eliminating the use 4of arudder. .This .pivotal movementmay be .effected manually, or by-hydraulic means, as will be described.

Still another important 'feature of Athe invention 'is the uprovision ofthe `expansion reservoir for the pressure iiuid.' Oil is preferred .aslthe pressure vuid andthe .term oil Willhereinafter be used, but itshould be understood that Aany desired pressure fluid may lbeusedinstead of oil. In hydraulic vsystems under pressure, especially wherethe driving imotor is .operating continuously, vthe oil vtends to"increase rapidly in pressure iand temperature, even in normaloperation, and especially if the hydraulic Amotor 'should jam. Increaseof pressure 'is `taken care of by f an overload by-'pass valve, vand'increase of temperature is 'taken care no'f bythe expansion reservoir,=of=a capacity "to allow `the oil to cool, 'and' wherein `vit drops toatmospheric pressure.

'The oil'under pressure may also be connected to drive other mechanismon the boat, such asfone or more Winches, for raising the anchor, etc.

Further advantages 4of `constructionand operation will be'described lbyreferenceto the accompanying drawing wherein:

Fig. lis a diagrammatic v#plan #view fof 1a, iboat provided with thehydraulic propulsion systemof this invention.

fFig. '2 'is a side 'view of fa modification.

Fig. 3 is a plan view of the structure of Fig. 2.

Figs. 4 and 5 are plan and side views of another modification.

Fig. 6 is a vertical cross section through a unit of the control valve.

Fig. 7 is a side view of a preferred mounting for the motor.

Referring now to these drawings, 2 indicates the hull of a small boat,having the usual stern 4. An internal combustion engine or other primemover 8 is mounted on a suitable resilient base of any desired type,such as springs, a thick block of rubber, or on rubber mountings, as iswell understood in the art of mounting machinery. In a typical mounting,motor 8 is mounted on a plurality of angle irons I I8, having horizontalwebs H2, through which mounting bolts H4, affixed at one end in boatbottom |28, are passed. Compression springs H6 are placed between boatbottom H2, and additional compression springs H8 are located betweenhorizontal webs I I2 and washers |22 which are held in a desirableposition by nuts I24. The motor drives an oil pump 8, connected to thepressure pipe I which leads oil under pressure to a multiple directioncontrol and overload valve assembly I2, which normally sends thepressure oil to pipe I4, which passes through or over the stern 4, anddelivers the pressure oil to a hydraulic motor I8 of the conventionalreversible type, directly connected to drive the shaft I1 of propellerI8. Engine 6 and pump 8 are mounted inboard. Motor I6 could be mountedinboard or outboard, as desired. The propellers could be fixed, as shownin Fig. 1, and steering effected by separate control of the propellers,as will be described in connection with Figs. 2-5. However, a`conventional rudder could be used, if desired, or one or bothpropellers could be mounted'to move about vertical axes, as shown inFigs. 2-5, for steering purposes.

After the oil leaves the motor I6, it enters pipe 28 which leads it backto the valve I2, which in turn delivers it into pipe 22 and thence intoexpansion reservoir 24, which in turn is connected by pipe 26vtothesuction side of the pump, thus completing the'oil circuit. Reservoir24 is open to atmospheric pressure and so permits expansion andcoolingvof the oil.

, A similar set of pipes, I4' and 28', leads oil to and from the secondmotor I8 connected to the driving shaft I1 of propeller I8', thereturning oil being passed by the multi-way valve I2 to pipe 22 andthence to the expansion reservoir 24.

One unit of valve I2, such as 28, delivers oil under pressure to eitherpipe I4 or 20, so that the propeller can be driven in either direction,inaccordance with the oil supply. In other words, where pipe I4 is underpressure, pipe '20 is the oil return pipe, and where is under pressure,I4 is the oil return pipe. Valve unit 28 is controlled by a piston 38,connected to rod 32, in turn controlled by a manually operated handle34, swinging movement of which reciprocates piston 30 back and forth, tosupply oil under pressure Vto either pipe I4 or 28, to drive thepropeller I8 forward or backward, intermediate positioning of handle 34serving to place piston 38 in various intermediate positions,corresponding to various Iintermediate `speeds forward or reverse. i

A second and similar unit of valve I2, such as 28', controlled by piston30', rod 32' and handle |28 and horizontal webs 34', effects a similarcontrol of motor I8' and propeller I8'.

Excess pressure from any cause, such as stoppage of the motor orpropeller, is taken care of 4by a by-pass overload valve, which ispreferably incorporated as part of the valve assembly 28, to bedescribed in more detail later.

The control of motors I8 and I8 is independent, so that steering isreadily effected by driving the motors at different speeds, or indifferent directions, for a sharp turn.

A third unit of valve I2, shown at 38, connected to pipes 38 and 48, andcontrolled by piston 42, rod 44 and handle 48, delivers oil in eitherdirection to a hydraulic motor 48, directly connected to a winch orother power mechanism 50, so that it may readily be driven in eitherdirection, for raising or lowering the anchor, for example.

Referring now to the modification shown in Fig. 2, where the motor andpropeller are pivoted for steering, a hydraulic motor 52, connected todrive shaft 53 of propeller 54, is mounted at the stern on a verticalrod 56, pivoted yto turn on a vertical axis in upper and lower brackets58 and 88, secured to the hull. Turning of this motor about its verticalaxis will evidently steer the boat. Such turning could be done manually,or by oil pressure. Where oil pressure is used, rod 58 is provided witha laterally extending arm 82 secured thereto, the outer end of which isslotted at 83 and connected by the slotv to an actuating arm 84, whicharm is moved back and forth by piston 88 working in a hydraulic cylinder68, oil under pressure being supplied to either side of the piston bypipes 10, controlled by a simple reversing valve like 28, Fig. 1, forsupplying oil under pressure to either side of the piston, for steeringthe boat as desired. l

Oil under pressure is supplied tol the motor 52 by' pipes I4 and 20,controlled by valves like 28 and 34, as in Fig. 1. Pipes I4 and 20 areconnected to the motor by iiexible hose 12.

Referring now to the modification shown in Figs. 4 and 5, where thehydraulic motor is above the water line, upper and lower brackets 14 and16 secured to the hull support a vertical housing 18, so that thehousing can turn in said brackets about a vertical axis. The hydraulicmotor 88 is carried by the upper end of the housing and drives avertical drive shaft 82, at the lower end of which is a bevel gear 84driving the bevel gear 85, connected to shaft 88 of propeller 81.

Housing 18 could be turned manually about its vertical axis forsteering, or it could be hydraulically controlled by a pistonl operatedarm 64, as already described in Fig. 3. Oil is supplied in eitherdirection to motor by flexible hose 12 as described in Fig. 3, to driveit forwardly or in reverse.

The control valve assembly I2 is preferably composed of a number ofsimilar units, like the unit 28 shown in detail in Fig. 6. This unit isprovided with a main oil passage 88, vcommunicating by passages I8", I4'and 20', with pressure pipe I8, and pipes I4 and 20, respectively. Themain oil passage 88 is connectible with passages 88 and 90 forming partof a U-shaped exhaust or return passage 9|, connected to the oil returnpipe 22 for leading oil back to reservoir 24.

The valve body is also provided with a pressure relief passage 92,communicating with passage 83 and so with main passage 88, and openingat its other end into exhaust passage 9|.v A

`comes excessive. .suiiicient for the valve vassembly l2.

able threaded.shaft-:96,frelieves `excess .pressure in vthexsystemandservesito `Eby-pass pressure oil to passage 9| if for any reason Itheoil pressure belOne 'overload relief valve is The flow of oil throughthevalve is controlled by piston 30, already described which is providedWith three enlarged lheads 89', -99 and 93', for opening and closingpassages x89, 90 and -9:3, 4respectively. Passages 89a, equalize thevpressure :on-.both sides of heads 89 and .90'.and so ybalance `thepiston 130.

.Pistonll is also provided-With aI centralzpassa'ge 95, in communicationwith lateral holes 96, 91 and 98, drille'dinfheads 99', '93 and 99',respectively.

The :valve operates fas follows:

With the yparts in neutral position asin Fig. 6, oil under pressure fromI passes into hole 91, flows both ways in 95, out thru holes 96 and 9Binto exhaust passage 9! and so no oil would be supplied to thecorresponding hydraulic motor.

To go forward, piston 39 is moved to the left, oil under pressurepassing from pipe I9, thru that part of passage 38 to the right of head93', out I4 to pipe I4 to the motor. Head 93 shuts off oil ow to 29' andpassage 89. Oil returning from the motor comes in thru pipe 29 andpasses thru part of 88 and out passage 89 to exhaust passage 9|.

To reverse the motor to back the boat, piston 39 is moved to the right,oil under pressure passing from pipe I9, thru that part of passage 88 tothe left of head 93', out 20 to pipe 20 to the motor. Head 93 shuts 01Toil flow to I4 and passage 90. Oil returning from the motor comes inthru pipe I4 and passes thru a part of 88 and part 99 to exhaust passage9|.

Intermediate positioning of piston 39 between the forward and reversepositions gives corresponding intermediate propeller speeds forward andreverse.

There has thus been described a hydraulic drive for a boat, wherein oneor more propellers can be driven in either direction at any desiredspeed without using mechanical clutches and gear shifts, and whereinsteering can be erlected by driving two propellers at different speeds,or by using one propeller and pivoting it to move about a vertical axis.This steering can also be done simply by manipulating a reversing valve.The entire installation is smooth and quiet, because the motor ismounted on a resilient, shock absorbing base, and so engine vibration isnot transmitted to the hull. |The usual propeller shaft, directlyconnected to the prime mover, is entirely eliminated, and the expense ofits installation and upkeep is of course eliminated.

A particularly important advantage of the installation is that eitherthe engine or propeller can very readily be disconnected for replacementor repair, simply by disconnecting the oil pipes and a few mountingbolts.

The provision of the expansion and cooling reservoir 2li is alsoimportant for allowing the oil to drop to atmospheric pressure and tocool off, thereby avoiding overheating of the oil, which is a seriousproblem, especially with more powerful engines.

While I have described the preferred ways of carrying out my invention,it should be understood that the invention is not to be limited to 6 thedetails illustrated, ibut .may fbe .icarried .out .in otherfways.

I claim as my invention: 1. :Propulsionimechanism :for ia boat, compris-.ing an engine, resilient, vibration absorbing .means .for .mountingsaiduengine, a .fluid pressure pump driven :by `saidengine, both =mountedinboard of the hull; a hydraulic motor, anda propellerr driven thereby,4braiclretzn'leans "for mount- .ing' said'motor andzpropeller 'outboardof the'hull; pipes,operativelyzconnecting said pump and Vsaid*.hydraulicvmotor; an'dfvalve means `.for controlling the :suppl-y `ofVpressure fluid to 'said hydraulic motor.

S2. Propulsion ymechanism fora boat, compris- .inganiengina a fluidpressure pump driven .by said engine, Aboth mounted linboard `of the;hull; .an :expansion reservoir ymounted inboard lof ythe hull; ahydraulic motor, and a wpropeller-:driven thereby, bracket meansior-mountingsaid motor .andpropeller outboard of 'the hull v pipes.-forleading fluid `under lpressure from lthe y pump :to the motor, thence tosaid reservoir, and thence to the suction side of the pump, and valvemeans for controlling the supply of pressure fluid in said pipes.

3. Propulsion mechanism for a boat, comprising an engine, resilient,vibration absorbing means for mounting said engine, a fluid pressurepump driven by said engine, both mounted inboard of the hull; anexpansion reservoir mounted inboard of the hull; a hydraulic motor, anda propeller driven thereby, mounted outboard of the hull; pipes forleading fluid under pressure from the pump to the motor, thence to saidreservoir, and thence to the suction side of the pump, and valve meansfor controlling the supply of pressure Iiuid in said pipes.

4. Propulsion mechanism for a boat, comprising an engine, a fluidpressure pump driven by said engine, both mounted inboard of the hull; aunitary assembly of a hydraulic motor and a propeller driven thereby,both mounted outboard of the hull; bracket means for said assembly ofmotor and propeller, mounted outboard of the hull, including means forpivotally mounting said assembly in said bracket means, to move about avertical axis for steering purposes; pipes for operatively connectingsaid pump and said hydraulic motor, and valve means for controlling theflow of pressure fluid to the hydraulic motor.

5. Propulsion mechanism for a boat, comprising an engine, a fluidpressure pump driven by said engine, both mounted inboard of the hull; aunitary assembly of a hydraulic motor and a propeller driven thereby,both mounted `outboard of the hull; bracket means for said assembly ofmotor and propeller, mounted outboard of the hull, including means forpivotally mounting said assembly in said bracket means, to move about aVertical axis for steering purposes, means, operated by pressure fluidfrom the pump, for effecting such pivotal steering movement of saidassembly, pipes for operatively connecting said pump and said hydraulicmotor, and valve means for controlling the fiow of pressure fluid to thesaid assembly of motor and propeller, mounted Y outboard of the hull,including means for pivotally mounting said assembly in said bracketmeans. to move about a Vertical axis for steering purposes, means,operated by pressure uid yfrom the pump, for effecting such pivotalsteering movement of the assembly, pipes for operatively connecting saidpump and said hydraulic motor, and valve means for controlling the ow ofpressure fluid to the hydraulic motor.

7. Propulsion mechanism for a boat, comprising i an engine, and a uidpressure pump driven thereby, both mounted inboard of the hull; anexpansion reservoir mounted inboard of the hull; a unitary assembly of ahydraulic motor and a propeller driven thereby; bracket means for saidassembly of motor and propeller, for mounting said assembly outboard ofthe hull, including means for pvotally mounting said assembly in saidbracket means to move about a vertical axis for steering purposes;means, operated by pressure fluid from the pump, for eiecting suchpivotal steering movement of the assembly, pipes for leading pressurefluid from the pump to the hydraulic motor, thence to the expansionreservoir and thence to the suction side of the pump; and Valve meansfor controlling the flow of pressure uid as described.

ERNEST C. C. MILL REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 366,652 Harthan July 19, 18871,257,825 Eklund Feb. 26, 1918 1,908,144 Gross May 9, 1933 2,046,558Hussman July 7, 1936 FOREIGN PATENTS Number Country Date 26,279 GreatBritain NcV. 15, 1912 308,141 Great Britain Mar. 21, 1929

